This invention pertains to a diesel fuel injection nozzle assembly for atomizing and spraying each charge of fuel, premixed with air, into the combustion chamber of a diesel engine cylinder.
Some early diesel engines employed an air-injection system, such that the fuel was atomized into the cylinder under air pressure. Although the system is known to have provided excellent smoke-free combustion, it required expensive and bulky multistage compressors and intercoolers for injection air. Consequently, with the advent of spray nozzles capable of sufficiently atomizing the fuel by use of fuel pressure alone, the solid or airless injection superseded the air-injection system with its bulky air supply equipment and has ever since become the generally accepted method of fuel injection in compression-ignition engines.
Recently, however, it is being contemplated to inject fuel into diesel engine cylinders at pressures in the order of 1000 kgf/cm.sup.2, with a view to higher engine efficiency and less exhaustion of air pollutants. The usual airless injection method does not necessarily provide good combustion at such ultrahigh pressures.